Question: What is the midline equation of $y=\cos\left(\dfrac{2\pi}{3} x\right)+2$ ? $y=$
Answer: Midline in sinusoids of the form $y=a\cos(bx+c)+d$ Graphically, the midline of a sinusoidal function is the horizontal line that passes exactly in the middle of its extreme values. The midline equation of a sinusoid of the form $y={a}\cos(bx + c) + {d}$ is equal to $y={d}$. [How can we justify this given our graphical understanding of midline?] Finding the midline The midline equation of $y=\cos\left(\dfrac{2\pi}{3} x\right)+{2}$ is $y={2}$.